Yes, it's the wrong time of the year to take cuttings.
Yes, you'll have trouble reducing leaf size, that's why they won't ever make a real decent bonsai.
And...if they are so plentyful in your area why in the world would you want to take cuttings? If you feel compelled to use them why not get a larger/established tree and work it back?

There are several other holly (hardy and small leaved) which will make excellent bonsai. Most will bud back with ease, more than you want.

Thanks for the information. With so many holly varieties, I thought it might be possible that one suitable for bonsai could escape the common list of bonsai-ables - but that seems to be wishful thinking.

I have actually taken some ilex opaca from the ground, and in trimming them, sought to use the scraps as cuttings. The thought was more about not being wasteful, and trying something new in the process.

You answered my main concern - that they will bud back. Generally speaking then, will those species that are technically coniferous but have a composition more like that of deciduous trees (such as the holly) behave closer to deciduous than not (with respect to back budding and cuttings)? This information would help me interpret which species to apply which techniques. Thanks!

I understand what you're trying to find out, but I don't think you can generalize as even plants more obviously of one type or another may not behave the same way, or may not do so in different environments, but look at it as a learning experience (though I wouldn't automatically apply the results to other trees :-).

Thanks for the advice. It sounds like the best thing for a beginner like me to do is to stick to the more common varieties used in bonsai.

I still will experiment with new things, and maybe having a bank of reliable bonsai will help me make judgments about the experiments. The other local tree that is plentiful (and gorgeous) is the Southern Live Oak ( Quercus Virginia )...