I would look into a pump that does double duty like this pump by Topeak.

I've never used co2 pumps before but I know pumping after 40psi becomes hard when you manually pump on the small pumps. I'm not sure how well the seals are on the co2 pumps and how long they will last once you've used some of the co2 and wish to keep the remaining unused portion for later. Personally I would use a co2 for topping up the tire after you've done the tire up to 40psi and use the co2 to pump up to the higher psi's.

I would prefer a pump that takes 12gm unthreaded tubes instead because any sports store, mega deptartment store, Wallys, etc types will have some area with pelletguns/paintball guns and you can buy the co2's there if your tube is run out. Best to buy a 25pak then the 5pack co2's. You get better value on a 25pack.

Pair this up with a nice pelletgun and you've got a nice combo.