Updated, some more recent sources fetched and packed. Works even better.
Finally I've managed to get my wireless card to work flawlessly in F7. By flawlessly I mean that there are no more chaotic disconnects and the whole thing seems immensely more stable (i.e. haven't spontaneously disconnected at all, even after heavy use of rtorrent).
The magic is that the development of kernel and wireless modules, and rtl8187 in particular, is going on, and on kernel.org available rtl8187 source seems to be really improved.
The wireless development is going on somewhere here:
and it was sufficient for me to fetch the rtl* files, modify makefile to add "all", and build a shiny new rtl8187.ko, which worked for me perfectly, and replaced the old one in /lib/modules/2.6.21-1.3228.fc7/kernel/drivers/net/wireless/mac80211/rtl818x/.
As this worked for me, I've thrown together a little archive -
sudo /sbin/rmmod rtl8187
sudo /sbin/insmod ./rtl8187.ko
sudo /sbin/ifup wlan0
and if that works, replace the original kernel module from /lib/modules.