Some more requirements would be useful. Is the user required to have these apps? Do you want the apps to be updatable through the market? here's my thoughts in lieu of that information ...
The problem with not going through the market is that they won't get update notices and won't see those apps in the "my apps" list in the market. i'd rethink that ... It's probably not what the user wants, unless you are installing for example enterprise apps that aren't on the market anyway.
You could for example create a "recommended apps" app. It can show your list of apps, and indicate which are installed, and link to the market install page. This of course doesn't force them to have the app installed, but this is actually a friendlier thing to do.
There's also nothing stopping you from creating your own market app. The tools are all there in the SDK. Personally, I'd hate this as a user and would prefer the lighter weight integration on top of the existing market I mentioned above.