I think its AWESOME that you are doing this. Small or large it can be done! Was the concern going from small to large the money factor or the amount of people or something else all together?
I have an "At home" business with The Body Shop At Home. I have done several showers. Here is how it worked. They had the bride pick several tihngs out of the catalog I came in and did a theme... facial, make up or a spa treatment. (THis is all free adn the host gets free products) The host always gave all the host benefits to the bride and most of the products were for the bride too. They have been a lot of fun and this really helped the host to cut back on costs as I supply all the products. She did have cake and food for after and everyone had a blast.
Check out my website
www.thebodyshopathome.com/web/faithjones
There are several independent business' out there you could pick from. Of course I would love to do it another idea is the pampered chef which then the consultant/guests actually make food.. and the bride picks out cookware which may be needed.
We have had them in the home or a local clubhouse/park district if it was bigger.
Do the best you can and everyone will enjoy it.