Gardening and Horticulture - "steel" swingset

My wife has just informed me that soon she will be purchasing a swingset from a retail store. I told her to give me a couple of days to gather and research some info on a swingset I can build myself. The problem with store purchased swingsets is they tailor to either smaller or older children. I explained that if I can find website or info on the "seats" and "slides" I'll be able to customize it to fit all ages (my wife runs a home daycare) from ages 2-12. I really dont care for the wood sets, I am more interested in the steel tubing. I can really use all the help I can get on this as far as seats, slides, and rings. Sorry it seems as though I wrote a book on this subject but I wanted to give the details.
Thanks in advance!

snoofer,
I don't mean to burst your bubble, but I would stick to the smaller plastic yard toys for the toddlers and that's about it. A mix of ten or twelve year olds amongst a few toddlers is asking for possible problems with a larger swing set. There are also possible liability issues. One head turn by supevision, could result in an injury to a toddler by a larger child, especially on a swing. And I know it can happen. My better half has been doing daycare for 16 years now (14 at a church and the last 2 in our home). A number of rules have been established here to avoid any possible complications.
I really think you should reconsider.
fred