Is it possible to have two seperate layouts, one for the index page and another for all other pages?

you can use "themechanger" module.
just clone your original theme and name it something else.
make all the adjustments on that theme.

if you would like for the same blocks to appear in different places, depending on how adjustable your theme is and what you want to do, you may have to edit the block tags in your theme template to appear in different areas.
however, then all blocks set for that particular column will appear there as well.

hope that helps some....

you can also use the MyPage module to make a unique home page, or any one of the other html wrappers, and then use the blocks section in the admin area to layout the rest of the site.

From what I hear, one of the possible features of XOOPS in the future will be individual layouts possible on each page.