I'm with JPF on this one, the non-top boost AC30s do have a great clean tone. Also, due to the fact it has fewer gain stages, the tone stays cleaner too.
The tone of a non-top boost AC30 with a Strat or Tele is magical.
If you do go down the vintage route, be aware that AC30s came in bass, normal and treble models. You'll only be able to tell this from looking inside the amp and it'll have this written on the chassis. A half decent tech will also know what components differentiate the three designations too. You can use any of the three for guitar, but they will each sound different - if in doubt, just plug in and see if it sounds decent.
I'm not sure about pricing these days, but the AC30 heads were quite a bargain in recent years and are exactly the same amp. If its for cleans, you'd get more mileage from an AC50 - cheaper and more headroom.
Even better is a Selmer Treble & Bass head - easily the equal of any Vox and a fraction of the price.