Ok here's the data sheet from Sanyo.
http://sanyo.wslogic.com/pdf/pdfs/HR-3U-2500.pdf
What it says is that on ths 2500mah cell, it will maintain a voltage minimum of 1v all the way to 2000mah discharge, and when it's fresh it hold 1.15v. This is with a 5 amp load on it.
So if the pack is anywhere near fully charged (or to be more accurate if the pack is not near dead) it will stay above 5 volts even at a 5 amp load. With 2 packs, that's 10 amps continuous output for 4/5 of its capacity. This is probaby more than the little R/C connectors will handle.
I do not see a problem here. 10 amps continuous, voltage always above 5v, save a pound over the sub-c cells.
TF
TF