<<TLDR Warning>> What's the difference between the A5's hopper and the X7's hopper, other than the fact that it's flatter on the top (making it look like a squashed and smoothened Richochet R5 hopper)? I'd be interested in buying one of those hoppers, if only to completely open up my line of sight through my red dot sight. The accessory rails are an excellent upgrade, in my opinion. I can see why you call it a cosmetic-only upgrade, but for people like me who don't like iron sights, it's one less thing to have to buy. The magazine is the cosmetic upgrade in my opinion, although it doubles as a "tool storage" container. I'd probably drop the smaller, straight magazine on there because there's be no way to lay flat on your stomach and fire with that huge block protruding out of the bottom. In all, I'd love to have one of these things, but it really looks like this is more like an "A5 v1.5". If you don't have a marker, this is a great place to start, but if you have an A5, then you're probably better off putting more money into the marker you have. In any event, I'd love to take a shot at designing a professional-grade Tippmann marker. I've been pretty good at designing [link=http://www.samkuo.net/ece110/P1000206.MOV]things[/link] in the past, so let me know what you think of this idea (if you can actually read the whole thing): I'd start with a [link=http://world.guns.ru/assault/as41-e.htm]F2000[/link] body--a newer "bullpup" design that internalizes most of the barrel (making the gun much shorter without compromizing accuracy). I'd leave everything alone, except for the the grenade launcher and sight, which would be optional. The most interesting departure from today's paintball markers is that this design would feature an internal hopper and feeder mechanism. To accomplish this, the entire stock would have to be hollowed out (including the part above the magazine), which would form an internal 100+ round hopper/loader. Just above where the magazine meets the body, I'd install a gigantic vertically-mounted, electrically powered cyclone feeder with an off-the-shelf laser emitter/sensor in the chamber that would verify that each shot was loaded before firing (even if you could pop the barrel out, paint breaks inside this thing would be something to avoid like the plague). To power the Cyclone feeder and laser system, the magazine would could hold a couple of AA NiMH rechargable batteries, which are available from any grocery store for about $20. The last thing that I'd do is to install a set of ports on either side of the stock for compressed gas and paintballs (remember, this thing has to be ambidextrous). In order to feed air and paint, I'd design a backpack with holster for a compressed-air tank and an integrated 500-1000 round reinforced rectangular hopper. To get the paint and air to the gun, a flexible .75 caliber hose with the air line spiraled around it would probably do the trick. In essence, the gun would be continuously fed paint in almost any natural standing position until you laid down or fired up at an extremely high angle that made it impossible for gravity to feed the gun's internal magazine. If that happened, you'd have that internal magazine to run off of. Based on the price of the A-5 and the assorted mods out there, I definitely think that something like this could be built and sold for under $500.