I have the same issue as well.
Like mjzglr, I use a Buffalo WHR-HP-G54 (using regular Tomato 1.28) as the main router due to its strong antenna.
I tried to use a ASUS RT-N12 (using tomato-K26-1.28.9054MIPSR2-beta-Std) as a wireless ethernet bridge, but it won't connect to the WHR-HP-G54. I just get a slow blinking wireless LED light.
I also tried a Linksys WRT160Nv3 (using tomato-K26-1.28.9054MIPSR2-beta-Std) and have the same problem, blinking wireless LED light.
Then I tried a Linksys WRT54GSv2 (using regular Tomato 1.28) and it connects fine to the WHR-HP-G54.
Like you guys, I believe it's a Broadcom driver problem since mjzglr mentioned DD-WRT has the same problem. It's up to Broadcom themselves to fix this issue in the driver, which I highly doubt they will.
For now, I'm just using the WRT54GSv2 as my only wireless bridge. If I need more bridges, I will probably buy a cheap Tomato-supported G router from eBay.
I cannot use the RT-N12 or WRT160Nv3 as my main router because I need a strong antenna. My block has many other wireless signals that interfere with my signal. Only the WHR-HP-G54 (out of my 4 routers) can break through the interference.