I think, because you're used to it, you're under-estimating the cognitive overhead of using the mouse. It also sounds like you've bought into some of the worst kind of vim evangelism, the kind that says effective vim users never hit j repeatedly to move between lines. Granted, it's not the best, but if you're moving only ten lines, V followed by repeated j takes basically no thought to create the selection. If it really bothers you, v followed by / will extend a selection to the match. I find that I mostly use / and ? to move around. In that context, setting hlsearch and incsearch might be helpful.

You might also want to use code folding, especially if moving blocks of code around is something you do a lot of. If you delete a fold in vim, the whole fold goes into the paste buffer.