Hello (blood)suckers out there!
It seems this question is popped up by every newly embraced kindred at one or another time.
And the answer is: no, it's impossible for technical reasons.
Bloodlines does not have a plugin system for user created mods, so the modders have to edit the gamefiles. And as every modder has his own ideas, every mod has different versions of the important game files. So if you install one mod, and then add another one, it leads to a mess that makes the maddest Malk look completely sane in comparison.
The limited inventory also adds to the impossibility to do it. You can't create new items for the game, you can only edit existing ones. So if a mod includes a new quest that needs a new item, an existing one has to go...
There have been some trials at building a compilation, but they generally change every mod involved so much, that it's not worth playing any more (IMO at least).
The only exception to this is burgermeisters clan quest mod. It does a rather good job of adding oteher content. But even that does change a lot of things.
You can usually add new skins without trouble. Things like the Arsenal Mod won't cause problems either, as no mod I know of uses weapons for something completely different. Music will be a problem with CE 1.4, but if you add the 1.45 patch, you'll have an easy to use option of putting your own music into the major clubs (Asylum, Confession, Asp Hole).
What you can do however, to avoid all this reinstalling stuff for different mods is using multiple copies of the game:
Install a fresh bloodlines game. Then copy everything from your bloodlines main directory (including subdirectories) to another folder. Install the mod you want to use into this copy and create a launcher on your desktop (vampire.exe in the base directory of the copy).
For most of the complete mods, you don't have to worry about patches to the game. They usually are based on Wesp's unofficial patches, usually in the version of the release time of the mod. And the unofficial patch also includes the official one that was released before Troika went buzz.
Hope this will explain most of your questions. If there are other things you want to know, just ask.
Remember, tere are nos stupid questions, only stupid answers, though we Antediluvians do love to give them