Hello CrossRoads,
I think you're on the right track. I finally had the flash of genius :~ to remove the 1ms delay in the transmitting code (more commands transmitted per ms), increase the transmission speed (more bits and bytes per ms) and increase the wait time (more bits arrive during wait period). The number of missed signals dropped significantly, and at 7000bps and 30ms wait time I didn't see a single missed signal anymore.
I also took a look at the VirtualWire code and yes, it seems it needs some time to figure out where the bits start and where the packets start so that it can return complete messages. I'm wondering whether the speed of "latching on" could be improved (coming from software development, this would be a nice algorithmic problem :-)).
Thanks,
Christoph