Hey folks, I've found that (Surprisingly) I'm really liking the tone I'm getting from my roland microcube, but I was wondering, could I hook it up to my louder amp (A fender superchamp) through the auxiliary input with a second cable?
Fender American Standard Telecaster
Vox Night Train 15W
An ever-morphing BOSS and MXR loaded pedalboard

"I eats more chicken any man ever seen!"
-Howlin' Wolf
As you stated it is an input, so no you can't output a signal.
I think the better option would be to get the bigger Roland Cube. However, I think your idea would work (Keep volumes low to start out with, just to be safe.)
Telecasters-->Dunlop Volume Pedal-T1M Pearl-AMT Japanese Girl Wah-Line 6 M9-Ibanez DE7-EHX Cathedral-->Mesa Boogie Nomad 4x10 combo