The FCB looks great, but it's pretty large - one of the reasons I got the the HX was to reduce my effects footprint.
I can change presets on the HX. All I need is something with a few buttons that send CC messages to either switch snapshots, or toggle blocks in the HX. The Softstep seems nice, and maybe there are some other options. But all are somewhat too large for me. I want to add them to the few inches of remaining free space on my pedalboard (which currently houses a Cali76 CB, HX, a Future Impact, and an SA Aftershock). I'll have to look into all this.
I'm in the same boat as you rd2rk, I'm a programmer so the software end is fine, but hardware is more scary for me. My daughter has done a few Arduino projects so maybe I'll enlist her help.
I can't help thinking that Line 6 should have included some inputs for extra footswitches to control the functions which they didn't have room for.