Just my thoughts on it, if you want a cab, go all the way. If you want a home console, leave the pc out in the open and use it like a game console. No point in hiding it in a box and poking at it with a stick to turn it on.
If you go the full cab route, there are a ton of options to help keep costs down. You've got most of the electronics already. You'd just need the boards to wire up your control panel. And an i-pac is what....$40 on Ultimarc.com. You can get a 2 player set of sticks and buttons for $35-$40 on ebay, or from one of the many vendors in the Buy/Sell/Trade forum here on BYOAC.
If you've got access to the tools and have space you can either build one to potentially save some cash, or buy a used cab and gut it to work for what you want. Or if you don't have the space and tools, there are some pre-made kits like you mentioned at recroommasters. You could go with the sit-down cab style if you wanted, so you're not playing NHL 94 standing up, and you could fit the 26" LCD in that cab. They've got a couple of standing style cabs for a decent price too.
You could go for a bartop style kit like several of the guys on the Buy/Sell/Trade forum here. One of those may fit a 26" monitor and fit the guts of your pc. They are affordable and don't require a ton of work to finish.
But ultimately it's up to you and what you want to spend money on. If you don't have cash to spend, you're gonna put more elbow grease into it to get where you want. If you are willing to drop more cash, the work-load can become lighter. It's up to you and ultimately what you want. If you want a glorified SNES console, you've got it already and just leave it hooked up and use it like you would a real game console. If you want an arcade cabinet, then I'm sure you don't want an ikea frankenstein thing with holes in it you poke with sticks.
