Putting 20 sites in one BIG hosting account will it effect SEO?

Hi

I am in the process of building several small sites which are about 22k in one big hosting account, I rekon I'll be building around 20 small sites with different domains redirecting
to each of these sites in a different folder on the host.

I just want to know will it effect my seo and will search engines spider these sites, so below is what I propose to do:

Site 1
www.gadget1.co.uk/gadgets/gadget1/index.html


Site 2
www.woodenduck.co.uk/gadgets/woodenduck/index.html

Site 3
www.penknife.co.uk/gadgets/penknife/index.html


Site 4
www.magicwand.co.uk/gadgets/magicwand/index.html

Manythanks
Shebs.

Just don't interlink them or you might get penalized.