Couple of considerations
Looks pretty sound. Just a couple of thoughts
1) Don't think you need the trim indicators. Skyview displays that I believe.
2) Dump the map box. May not work there with structure behind.
3) Dump the Hobbs meter, the Skyview will cover your times
4) Suggest getting rid of the SL30 for a SL40. You probably don't need a backup NAV. Probably never use the one
This will save some money
5) Move the Boost pump switch closer to throttle for emergencies.
Also just a bit of improvement on the flow of your switches. I'd put all the switches in a nice row along the bottom of the EFIS in level of importance. Master, avionics, Auto Pilot, Pitot heat, Position, Strobes, landing, Cabin, Dimmer.
If you remove the trim indicators you could put your mag switches above the start switch, keeping those away from the other switches.
Looks good!!! You might wait till after Oshkosh to finalize. Heard there's some neat stuff coming out at that time
Could sway your decision.