I've been able to link two dir-655 together with absolutely no problem and issue. I'm still using 1.21 firmware but I doubt this will have nothing to do with your difficulties.
My main router is set to 192.168.0.1 with a DHCP range of 192.168.0.101-149.
Here is what I did in my second dir-655 :
1) Reset the 2nd 655 to factory default (no advenced features like port fowarding, routing, ect)
2) Then under "setup" and "network setting" of the 2nd 655, I have set a static ip adress of 192.168.0.2 along with the same subnet mask adress of the main router 255.255.255.0.
3) I have deactivated the DHCP server in the 2nd 655.
4) Save settings and then once all is done, I've connected one of the main router lan port to the lan port 1 (any port will work) of the 2nd dir-655.
5) I am able to acces the main router at 192.168.0.1 and the second one at 192.168.0.2.
6) I have set wireless settings exactly the same except the main 655 is fixed to channel 1 and the 2nd 655 is set to chan 11 (which won't overlap if you are using 40MHz bandwidth). I have disable auto scan feature on both routers. I gave both router the same SSID and exact same encryption.
Result : everything work great. Laptop and mobile phones roaming work great (windows 7 and android 2.2)
I've done a test by accessing directly the 2nd 655 directly when I connect my laptop direcly to it by wire. I just set the laptop ip to a fixed adress (192.168.0.25 with subnet 255.255.255.0 and did not put nothing in DNS) and I can access the 2nd 655 right away by typing 192.168.0.2.
I don't see what you are doing wrong since I looks pretty much the same way I did my setup here...