Bottled my batch today. Things I noted:
1.) No issues with the rum stunting secondary fermentation. It kicked right back off in secondary, so much so that I ended up placing a blow-off, though it never made it to the tube. In the beginning, the banana mash floated on the top, and sort of held the CO2 down, rising with the bubbles instead of letting it pass. I would shake the carboy to get the whole thing to settle as needed.
2.) TRUB LOSSES ARE HUGE on this one. I had over 2.5 gallons in secondary, and barely got 13 16oz bottles out of it (so about 1.6 gallons). The banana settles to the bottom as it ferments, but never really compacts like a yeast cake will. I ended up using the "hop bag over the racking cane" trick to keep from sucking banana into the bottling bucket. But even with pushing for every drop, that's all I got. If you think you're going to like this one, go for a full batch. If you really want to just do a partial, make sure you account for the loss.
3.) FG was 1.015 @ 67F, so no complaints there. I know this tells me absolutely nothing about actual alcohol content. The warm feeling in my belly from the SG sample is telling me something, though... I'm guessing we're close to 9% after the banana addition.
4.) TASTE: speaking of the SG sample... at 67 degrees and uncarbonated, it is interesting. The nose is 100% bananas, the taste has a banana finish but is a bit strong on the rum. I'm going to do what folks say and let it age and carb until Turkey Day then see how it's doing.

<-- perfect emoticon for this thread
Ike