In a sense, the question ties into what a provisional patent application is. There is NO SUCH THING as a provisional patent.
When you file a provisional patent application, you are simply depositing your specification (and you SHOULD be depositing at least SOME claims) with the patent office that HOPEFULLY thoroughly discloses your invention (and possible variations of it - even if they aren't as good, in your opinion - and variations of it applied to other fields, and ...). This only sets a filing date that establishes that you were in possession of WHAT WAS DISCLOSED as of the day you filed the application. ... and the filing date is only good if you file a 'real' (non-provisional) application WITHIN ONE YEAR. If you file it later than that, your own provisional application can bar you from a patent.
You are only supposed to submit one invention per application. Trying to bundle them together is asking for problems (for a discussion of a few of the problems, see http://www.intelproplaw.com/ip_forum/index.php?topic=20908.0), unless they are actually two aspects of a single invention. You seem to indicate they are not. However, it depends on what your INVENTION is, not your product (I might invent a new laptop screen, but my product might be the whole laptop, for example).
At the very least, if you bundle too much together, when you file the real/non-provisional application, you will have to split it out into multiple applications that all claim priority to the one provisional. This can happen in an honest situation. Trying to keep it as separate as possible, though, is usually best. Unless you're rich or a prolific inventor, the filing fee for a provisional application is about $65 - so it's typically better safe than sorry.