Has anyone tried downsizing tender-drives yet?

Has anyone out there had any luck with making more reasonably-sized tenders for the tender-drive engines like Emily, Molly, and Hank? I'm really curious how they would look with slightly shorter tenders, and I would imagine it would be perfectly possible to make it run with a smaller tender as well, since motors and batteries can be very very small nowadays. I mean, just look at Plarail Advance and N-scale model trains.

I'm thinking around the same size as the older tender engines' tenders, Edward, Henry, Gordon and James. 4 wheels, all rather close together.

A smaller motor/battery isn't enough. Those C battery tenders (E/H/G/J) are clearly too short for this. In addition to the motor, they also need a gearbox (for torque, going up slopes, etc.) and a unique type of on/off switch that dis/engages with it (for the ability to freewheel). While there might be room for an N20 gear motor +battery in a shortened tender, the driven axle would still be permanently engaged. In Emily's case, the tender is too tall but not too long.

Update: this new thread might give you an idea on how to shorten a powered tender while still keeping the OG drive unit (just with the front of the casing cut off).