So I have searched the forum but haven't found anything that helps. I have an 2001 M750 with 36K on it and the rear shock is terrible and sags quite a bit. Is there a rear shock that is compatible with an 2001 M750 that is better than the stock that will drop right in? I would like to upgrade to something better but do not want to spend the money for an Ohlins. Thanks for your help!
The options that I've seen are to get a less used stock shock to drop in (you can find M750 shocks with ~10k on them pretty regularly and cheap on eBay), pay an arm and a leg for an Ohlins or Penske unit, or you could try to find a more adjustable / better shock from an 8xx series bike to swap in (I think that option is detailed on ducatisuite.com). You can also get replacement spring coils and keep the same shock, if you just want a new spring rate and don't mind the damping characteristics of the one that you have.
You can also try just adjusting your stock shock and seeing how much you can improve it. I don't know what you mean by 'the rear shock (...) sags quite a bit', but it seems like a preload adjustment would take care of that. There are a few tutorials on adjusting your suspension on the forum, I believe.
There are regularly used ohlins that pop up, that's what I did for my M900 and got it about half of retail
Don't know anything about Hagon shocks from UK but may be worth a look
http://stores.ebay.com.au/bits4motorbikes/Ducati-/_i.html?_fsub=1902114017&_sid=82758647&_trksid=p4634.c0.m322 (http://stores.ebay.com.au/bits4motorbikes/Ducati-/_i.html?_fsub=1902114017&_sid=82758647&_trksid=p4634.c0.m322)
If the chrome on the shaft is still good you can get it rebuilt, and even upgrade with a linear spring for your weight and custom valving.