The Compute Module (all varieties) are definitely not discontinued.
We have seen a significant increase in demand this year on the CM3 and CM3/Lite which has meant that both our partners have been working hard to get the product back into stock.
The current position is you should be able to get CM3 on a maximum of 4wks lead time for quantities in the '1000's (larger quantities I would strongly recommend you talk to your distributor about forecasting future demands or placing scheduled orders).
Looking at the position as of this morning - Farnell have 1200 pcs free stock on 21 July with a further 10k pcs 9 August and 15k pcs 8 September. RS are currently showing a free stock date of 31 August which I know they are working to improve.
In terms of CM3/Lite, RS have 3k pcs in stock in Europe now. Farnell have 1.9k pcs available 21 July and a further 8k pcs 29 July and 7.4k pcs 8 September.
I hope this helps!!