the cabinet I sent is predrilled, that was part of how cool it was... has a nice hole on the top, and an opening on the back as well. also come in white. It also looks like their double thick pressboard, which is nicer than the 3/4" stuff, but I hear you. When I saw it, I imagined getting hte white one, and buying a birch bark sticker pack to wrap around it... I've seen them on housewares sites. would look cool wrapped in birch. or bamboo. or just leaves. another nice option is the mini rolling ikea lockers, but you'd want to remove the casters. They have 1.5" round holes in the back I think. or the bottom. I forget. I have a white ikea countertop underneath my 2 tanks in the living room, and the white pressed on surface they use is actually very easy to keep clean... something to think about.
The hard part of finding a 24" tall table, is that ergonomically, tables are usually closer to 29" or 16-18". stuff in between is usually things like underdesk cabinets, file cabinets, childrens furniture... 24" wide is also less common, a lot of sideboards are designed around the 16-18" or 32" mark, to accomodate the space between windows and doorways, which is usually dictated by the 16" on center studs in walls. (lol. sorry for the expanded furniture theory!)
ventilation is hard to predict, but I've found in my 5g palu, the gap front and back of the glass isn't enough to keep the glass clear WHERE THE cork is 2" from the glass in the front. but on the left front, the glass is usually clear, except the bottom 1" near the waterline. In the 45cube I'm holding moss in, there is a 1/16" gap across the front, and I still get almost total coverage of water on glass. at 70% humidity, according to my crap zoo med gauge. (almost wrote guage!)
A cheap electric fan built into a tube seems to be the way a lot of the froggers go for in tank ventilation. I've seen a few cool ones, covered in moss etc. Less loss of humidity, but enough movement to keep the glass clear and plants happy. Don't know if you'll need one, but if you do, it's an easy chore.
A 1/4" line might not be the best choice for a siphon. I'd go for 1/2" or larger. You want waterlogged coco fiber to be able to pass. you want leaves to be able to pass. Somehow, some of this will end up in the drainage layer. no matter how careful you are with screening etc.
You could use mesh at the bottom of your standpipe, I have an easy design in mind, and that should keep gunk out of the siphon, but the mesh can also clog, and then you have no way of unclogging it, without backflushing into the drainage layer. Anything designed to really prevent clogging, will usually clog if not cleaned. This is part of the beauty of a drain, you just have a valve under the tank. open the valve, and you can stick a chopstick or pipecleaner up through it to unclog it if it gets clogged.
If you go the standpipe way, I would use a 1.5" pipe, with a coco-hut style cave opening cut into the bottom of the pipe, so that it sits flush to the bottom of the tank, and has a side opening. Then you can easily send a rigid 1/2" line down the standpipe, or almost anything else you might need to run down it. You could also use it as conduit if you decide you want misters in the bottom of the tank... simplifying your plumbing and hiding. You can also put a cap on the top of the 1.5" pipe, ensuring frogs and insects don't get down in there.
If you use epiweb or some capliary foam for the background, you'll have an easy go at hiding your standpipe...