Admin category selection: Text form with ajax auto suggest instead of checkbox

Well i want to have more categories and subcategories. Lets say 1000 categories.

I don’t want categories as checkboxes. I mean i don’t want this
http://img33.imageshack.us/img33/6616/c5d17aa4a8f4411f901194e.png

I want them as a simple text box with ajax auto suggest.

Lets say i have a category called “main category”. It has two subcategories called “sub1” and “sub2”. When a user input “ma” then ajax has to suggest “main category”. if “main category” selected then i have to show another text form for subcategories. Something like this

http://img641.imageshack.us/img641/2568/948dfeca5a15474fbffd258.png

Is it possible? Any plugin available?.

The thing is i want the category select as easy as possible. Is there any plugin available?. Or can you recommend some other way to accomplish job.

Thanks.