Im thinking of making myself a Phone cover with a node build into it. It will sit flat on the back of the phone, so for that I need the thinnest lora/MT bluetooth board/chip I can find. So far Im considering the RAK19003 or a Heltec wireless stick with the battery connector removed. Even a standalone chip/board should be usable as I can program it before mounting it.
Any suggestions for what board to use?
I’ve been tempted to try this. There are lots of RP2040 based boards very load profile, which is what would probably try. Using USB for connectivity, rather than bluetooth. But its just theoretical, as havent tried it yet. In particular havent got round to trying to get meshtastic running on such devices. Likely to need a custom build of the firmware.
Sorry, that doesn’t actually help you!
Only other thought, maybe a custom broad. Cheapest node so far - #42 by Nestpebble - could be made very low profile. I think all components on one side, and through hole components could be avoided.
Includes an integrated lora antenna.
Have just found this, which seems quite nice
MIght serve as inspration. Havent tried it as seems to be 915mhz for North America, not sure if will work with 868mhz. In theory it might not sure.
The listing on tindie seems to imply its actally a Heltec Wireless Stick v3 inside, so close to what you thinking! Cusiouslly seems to include a screen, but there is no window on the case. WOnder if removed, or still there using battery? Or maybe its actully the wireless stick lite, which would make more sense.
I think I can do it thinner 
I am leaning more and more to use a Rak module so I can use a smaller battery. My wireless stick node burns close to close to 130mAh vs 14mAh on the RAK. Can use a very much smaller and thinner li-po cell. I want at a minimum 24 hour battery time. That means a 3000mAh for the Stick vs 400mah for the RAK.
Desoldering the solar and battery connector makes it even thinner.
They “stole” my idea of using wireless charging from the phone. I am planning on having a wireless charger board in it as well so I can keep the case as closed as possible.
Mine will probably feature a home made Dipole antennae as they are super easy to make and fit perfectly lenght wise on my phone. A Nano VNA is on its way from Evil Bay for fine tuning.
Although the RAK PCB antennaes are actually really good and small.
All put into a full phone case 3d printet out of TPU.
Main problem is that it is way better to have the radio up high and the phone in your hand or pocket. While on the phone the lora radio does not work real well.
This is true garth, but Im not going for a range record device here. Just a travel and everyday carry node. A lot easier than dragging a seperate module with me all the time to keep an eye on all the nodes I have in my MT network. My farmer friend is also using MT to track his livestock and other things around the farm, so a phone node like this would make his life easier as well.
The antenna will sit in the corner of the case having less than 90degrees blocked by the phone.
My MT network gives me a very strong signal most of the places I am at home, and i have a permanent mqqt connected node that will give my phone node access to my home network wherever I am in the world as long as my phone has an internet connection. ( its very important to keep track of my friends cows from aborad… 
)
I also air travel a lot and get very boored, so I bring a node to see how many nodes I can pick up from the air and connect to. A phone sitting in the airplane window is a lot less questionable than a 3d printed case with an antennae. Especially when the power button on my travel node also make it look like an ACME remote detonator.
Considering Ive managed to send messages to my wife @ +200km distance from the air with a terribly tuned original Heltec nubby antennae, a well tuned dipole will be quite sufficent for my use. And the way I hold my phone I will not block it with my hand either.
Ye, agreed. Not really looking for range, just convenient carry factor. Particularly that it can ‘share’ the battery of the phone, so not a seperate device to keep charged.
… for example for around the house, only needing the local node to connect to router on the roof (for example)
An antenna on back of phone will never be great, but can hold my heltec v3 on back of phone, with it little wire antenna, and connects to nearby router ok.
Also wondered about a retractable whip antenna, would be very retro!
I used to sell a magsafe model and had the same parameters in mind, the range was much worse than I expected. Sounds like a great plan and falls down in practice by being too close to both a phone and a sack of water. It did work well at burning man, but that was about it.
That’s useful context, thanks.
Certainly for a commercial product, easy for unrealistic expectations.
Admittedly havent tried them but expect many of the lora watches will make disappointing general purpose nodes. With very limited range, imagine a small chip antenna on wrist is not going to have very good all round signal. (aside from the battery life issues!)