Ah, I get it now.
Love how your mind works, Richard, and the solution is up to Steven of course, but my 2 cents is that playing albums is too large a paradigm shift away from what AutoDJ is designed to do.
I don't know if autoplaylists could connect to the lastFM API, but it seems to me that it would be more appropriate as an autoplaylist rule rather than an autoDJ feature, especially since it's already got the 'group by album' feature.
There might be a possible solution already built-in:
· Go to AutoDJ and enter a sensible figure for 'rated by lastFM as more than X% similar
(try something like 30% and see if you can increase it later; how successful it is depends on the size and diversity of your library)
· Go to album and tracks view
· right-click your seed artist
· choose: play more -> play similar '[artist name]'
When I do this, I get a Now Playing List populated with similar artists, and they are grouped by album (apparently because the view was grouped by album when I used the 'play more' option).
Another option might be to use AutoDJ to populate the Now Playing List with with single tracks using the lastFM similarity option, but then turn on shuffle and set it to 'shuffle by album'. You might not get entire albums placed in the NPL, but it will at least play the partial albums in sequence.
Finally, manually mapping similar artists/albums together using custom genres or moods might work better than a lastFM lookup.