I will second Thom's suggestion for the Defeet Duraglove, he turned me onto these over a year ago and I've been very pleased. Like you I was looking for something more resilient than merino liners of the smartwool and ibex variety and the Duraglove is considerably warmer and handles wood fire tasks and scrambling around on rock well.
My system is similar to yours in warmth and flexibility, minus the mitts, other than extreme cold (*which I avoid like the plague) this setup has worked well and doesn't have any gaps for me, is relatively inexpensive, warm, and durable for tinkering with wood stoves and such:
Defeet Duraglove + MLD eVent mitt (seam sealed!) (Good down to 32F)
Lighter merino liners + OR Omni glove + MLD eVent mitt (everything else south of freezing)