why not just have a "extras" option menu? the very base game settings are used to load the game, and users (or auto-detect if we are lucky) will turn on settings as they see fit, if for example "transparency" is off, it ignores the Transparent textures entirely and renders normal.
however placing a "transparent" block means you hold [button] it begins at 0%, and goes to 100%, in say 5% increments.
gives those with the grunt the nice effect, and allows those without to run standard, even better the code could be implemented, and a example pack could be released, and the community would pick up the optional pack.