+1 on the C-Max Energi although I saw on edmunds.com that they didn't think it would be available now until early '13; the hybrid version possibly by late '12. I did come across something on the differences between the hybrid only versus plug-in hybrid cargo capacity as we're looking at the utility aspect. Perhaps old news but you'll lose about 11 cu. ft. with the battery packs versus the non plug-in (or 43.4 with seats folded) -- this compares with 67.3 with a Prius V (not plug-in version, not available yet), 65.4 Mazda CX-5, 70 Scion xB, 70.9 Honda CR-V, new '13 Escape at 68.1 and even 53.4 with a Kia Soul; perhaps not everyone will cross-shop these but we would be downsizing from a VW Routan (at 144 total, 32.7 behind third row ... we normally travel with the third seat folded down so will be looking at what that space typically would be for comparison). For anyone who has something big like a minivan, you don't even have to think most times about something fitting, just fold down that third seat and it typically fits. Question is how many times do we need excess room ... researching that now, it also needs to have a great long distance ride (about 40% used for that) as well as great MPG on short trips otherwise we'll simply keep what we have. No question our LEAF is doing quite well as our main weekend errand runner in all but much longer runs or when more room is needed but for winter, utility and trips -- a C-Max Energi could be the ticket. Trade off on waiting is to balance how much the trade-in loses value versus getting something sooner as well as gas prices, etc. and piece of mind to unload it while it's still under warranty ... we had somewhat of the same thing with the LEAF purchase keeping our trade-in under 60K for max allowance.
EDIT: found the cargo dimension for the Routan with third rear seat 'out' for '12 (ours is an '09); as they only fold flat into a well and don't get removed like the older ones probably just a typo but it's 83.3 which blows away all of the above and is almost double what the Energi would hold. Of course we don't typically fill the entire space but it's convenient when you have it. It's hard to have max utility as well as max mileage otherwise someone would have figured it out a long time ago!