Discovered a strange problem with 2 7200 routers connected to one another.
This router
RTRISP1#sh int s1/0
Serial1/0 is up, line protocol is down
Hardware is M4T
Description: DCE Serial link to CCP1.com
Internet address is 130.3.3.1/30
will run approximately 5 to 10 minutes then drop connection with this status
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 138
Queueing strategy: weighted fair
Output queue: 44/1000/64/138 (size/max total/threshold/drops)

From This router

RTR2#sh int s1/2
Serial1/2 is up, line protocol is down
Hardware is M4T
Description: DTE Serial link to ISP Router$FW_OUTSIDE$
Internet address is 130.3.3.2/30
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)

I tried a second 7200 and it does the same thing.
Put a non-7200 and works fine.

I just tried to replicate your scenario on my Windows 7 64 bit machine and everything worked fine. I directly connected(no switch in-between) two c7200 routers and let them run for 30 minutes with no disconnection issues. I'm running the beta 2 version of GNS3. BTW, I was using serial connections.

I am running 086 on W7.
I put the 7200 back in the config, like clock-work, disconnects......
Really weird.....I am using Serial links also...