I had the same issue with the same firmware. I am using the modem in bridge mode with my WNDR3700 router. I am located in the east end of Ottawa.
This is my disconnection log from the week leading up to the tech visit
Internet disconnected] Sunday, January 08,2012 21:24:04
Internet disconnected Sunday, January 08,2012 16:36:40
Internet disconnected Sunday, January 08,2012 13:19:19
Internet disconnected Sunday, January 08,2012 10:04:27
Internet disconnected Saturday, January 07,2012 04:48:11
Internet disconnected Saturday, January 07,2012 00:34:31
Internet disconnected Thursday, January 05,2012 08:37:55
Internet disconnected Thursday, January 05,2012 03:52:55
Internet disconnected Monday, January 02,2012 07:20:29
Internet disconnected Saturday, December 31,2011 16:51:58
Internet disconnected Saturday, December 31,2011 15:37:49
Internet disconnected Friday, December 30,2011 05:33:55
I pestered teksavvy as my install was still under the one month warranty. They escalated to Bell, and a Bell contractor came out. I explained the issue and showed him the reboot logs that were identical to yours. He had brought along a Bell Cellpipe modem with firmware 188.8.131.52EF-ISAM and I attached that. He got permission from his supervisor to leave that modem at my apt and have me monitor. It has been almost a week and I have not had a single disconnect.
reply to Phibian
here's how to get 2 sagemcoms:
get DSL directly from bell (25/7 is $27 right now)
that's the first sagemcom. tell them you lost it/ate it/set it on fire and pay for another one. do that again and bam. two sagemcoms.
cellpipe is still connected.
hpna is an option somewhere i seem to recall.