Multisite Plugin Question – Can I suppress some?

I’ve set up a multisite blog .. and have some plugins.

1) ones I want sitewide activated are in the ../mu-plugins .. so everybody gets benefit or to function better on all sites as the default and others have no choice to deactivate // no problems.

2) ones I want for myself, and feel okay if I were a user of mine I would also want them (like contact form, twitter tools, etc). I set it on the admin blog and Network Activated, and it is not only available on each new blog it is also activated. // no problems

3) But I also have plugins that I only want in the admin blog and do NOT activate network wide. However, in the individual sites these plugins show up in the Plugin menu .. (e.g. admin type of plugins and specially for me plugins, and the like) // not what I want!
>> for instance: users can activate that cets_blog_defaults although I don’t believe the options actually show up because it only shows up in the admin’s superadmin menu but still..

I’m not sure if it even exists or not – but I would like to know if

(a) is possible to suppress plugins selected only on the admin blog from the multisites, and
(b) while I’m asking, is it possible to prevent users from actually uploading new plugins and just be able to activate plugins that I have selected okay for use as admin? (reasoning: so I don’t have a gabillion different stat plugins eating up my CPU resources etc)

Thanks!
HART aka PetLvr