I had an idea which I think would be reasonably simple to develop (tho beyond me as a n00b to Moodle coding), which was, on all blocks which are not already at the top or bottom of a page, to have 'to top' and 'to bottom' buttons in the block's header. Sample examples:
That's it! Sometimes the little things can make a big difference.
I would also encourage everyone who has an interest in Moodle development to pop by the tracker and cast your vote for those bugs, improvements or new features which have been proposed but are not yet fixed/implemented.
Cheers.