i was thinking about that the other day, my buddies C5 has it all in one, you press a button and the key pops out like a switch blade. you can always make one yourself if you've got the time. just rip the electronics from the inside, cut the top of the key off, get one from another car and just switch them over. maybe be a nice weekend project....
the main prob is that the main board of the remote control is really big sized and it does not fit in for example vw and mercedes pop up blade covers. so i am serching for some aftermarket parts, there are so many cars that use this control, so i bet there has to be an aftermarket replacement - or i hope there is
Ronin, i think that you can fit our electronics and key onto the citroen xsara one without a problem. Im gonna have my buddy ask his freind at Citroen to see if i can get one for cheap.
only thing I've seen for keyless entry is different colored replacement shells for the key fob, at the GM dealership here. They're not covers, it's an actual replacement shell.