Thanks to all who quickly responded.
To answer one question - I wouldn't buy from
the big box stores. There is a regional family
owned store that is like a HD (without the appliances)
that I shop at regularly that I have a discount card
The cabinet supply company is a "wee bit" further
drive from me, so I was wondering if it made sense
to go up to them to get the MDF. Sounds like it
could be. At least at the wood supply place, they have some
nice Russian birch that I could also use!
The downside - it's a cash only business!
Thanks again to all!