SAVE THEM !

Ditto.

Are you planning on having them stained or painted? If you're just repainting them, that isn't that tough.

Since you're short on doors for your expansion, have a custom door store build you some like it to keep the look of your house.

From another old house owner...my personal suggestion: Please save & restore them. It's not that hard, and by "not" repainting them, they can truly be showcase pieces in your home. Remove them one at a time. Take out to a back deck or patio area.

You will need:
1) A good heat gun. I have extensively used my Wagner for years. After about 6 years, my first one finally siezed up. It owed me nothing! Approx $30 at Lowes. Also, get some scrapers. I use the ones with the yellow handles from Lowes. They are flexible. Too stiff will dig into wood. Also get some cheap toothbrushes & a small can of paint remover.

**Heat gun & scrapers are great for the large areas on the door & paint remover & toothbrushes are good for tight areas or more detailed spots.

2) Palm sander (mine has sqare shaped sanding surface) Had a Craftsman. Piece of garbage. Didn't last one year. I kept the plastic plate thing that pokes holes through the sandpaper. Then purchased a Porter Cable...takes a beating! Had it over 6 years. Get some mid to fine grit sandpaper. The big square sheets can be quartered perfectly to fit the head size of the square sander.

3) Linseed oil & turpentine. These 2 in a 50/50 mix can be brushed onto bare wood & you will be pleasantly surprised how beautiful the wood grain looks! Let this soak in for at least 1 full day. Wipe off any extra oil.

4) Shellac. All my wood trim has a honey colored look to it. I believe they used Amber shellac. Most common brand is Zinnser. My doors are different. They had mixed Garnet shellac. You can buy these in flakes & you mix them with denatured alcohol.
Great article: http://www.theunpluggedwoodshop.com/shellac-attack.html

It takes a little time & patience to get the heat level & distance from door/paint just right. I'd start on low. You'll get the hang of how close to hold the heat & as it begins to bubble up, start scraping & wiping loose paint onto old newspapers.

I'm sure you're a little aprehensive about trying this, but I can assure you, once you do this one time you'll feel like a pro! You will save a tone of $$ & have the bragging rights to making your doors gorgeous again!

Take the $ you've saved & hit an architectural salvage place & get yourself some sweet glass doorknobs! The one below is mine. It needs a little touch up & with shellac...I can wipe down the alligatored area with denatured alcohol to smooth it out & put another coat of shellac directly on top. It has a way of melting/blending into itself. Amazing stuff & 100% natural. It's made from shell bugs!
http://en.wikipedia.org/wiki/Shellac

Oh...one more thing...new doors, even if they are wood, will not have the structural integrity or density of your old growth wooden ones you have. Those a gems. You just hadn't realized it yet! :0)