yeah a coder would know what your talking about. If I needed to do it I for myself I could sort out doing an overlay with just a few searches on g00gle, but I don't know where your level of skills are. Doing a div overlay was pretty common for changing the look of myspace pages when they were on top of the heap. Basically what happens is the page loads with a starting stylesheet and then after it loads all that content then a new stylesheet will cover eveything up and the landing page you want to be seen will be what is show to the viewer. But if you view the source you will see that all the content is still there in the html file, so the spiders will still be seeing it.
Try searching g00gle for myspace layouts and overlay codes. Just be careful cause a lot of those sites are full of spyware too. The best sites are the tutorial sites more so than the cut and paste sites. Most of my css knowledge started out by doing myspace layouts for local bands and businesses, but its been a while now since I've done that. If you don't already have some experience try searching for a basic css tutorial too. There are thousands of them, and it is pretty easy to get the basics of css from those tutorial sites.
Sorry can't be more help on the details. Would still be nice to hear from someone experienced about whether this will red flag anything for the se spiders.
edit - If you do decide to try the overlay method, be sure to come back and let us know how it affects your ranking. If doing this doesn't cause a hit on your ranking, then potentially you could just really stuff the hell out of your page with keywords. This would be so easy do do, I'd really be interested in knowing the results of anyones experimenting.
If your wanting to do it with iframes you can do a search on BHW for "cpa iframes" and get a lot of good hits. Here is one that I found, don't know if it's what your needing but it looks pretty good.
http://www.blackhatworld.com/blackhat-seo/cpa/37204-fake-referrer-cpa.html
I still like the overlay idea though, I might have to experiment with it myself sometime when I have more time.

Just be sure to keep the css simple in both the starting style and the overlay. The first layout will show for a moment as it loads, until the overlay covers it up. The faster that can flash past the better. The simpler the css the faster it will happen.