Interesting, I think I may have to get one of these. Just got a spangly new DH bike, and although it's insured, if it goes walkies it would be great to just go and pick it up.
The only problem I can forsee with using these on high end road/mtb's is that, like mine, most are custom build and easily recogniseable. They appeal to the pro bike thief, who will have buyers for the parts already, and it will more than likely be in pieces by the time you realise it's gone. At this point they would have found it unless it is buried deep inside the frame. The good thing about electric bikes is that they are certinly not appealing to the pro thief, so are less likely to be split. Hence a tracker would probably remain un-discovered for longer.
Maybe the answer would be to mount it inside the steerer tube, using a star fangled nut to hold it in place as these still have gaps in them? I once used this exact method to hide some sardines in a friends race bike. They went undetected for 5 weeks
The best bit about it all was he has a people carrier, so the bike was inside with him when he went to Scotland to race (from Bournemouth....lol) not on a carrier, the smell was epic, as was his face upon return. For the record we are actually good friends, and it was a revenge strike for something he did to me previously.
Another possibility would be to mount in the frame and make your own antennea extension that could come through a bottle mount perhaps? I am definately going to get one and do some testing!
Regards
Lloyd