What to make with leftover lamb roast

I would "hunk-up" the lamb and make some individual size dishes that you can freeze for later. Shepards pie, lamb pot pie, and the tagine are all excellent choices - but spend a bit of time now to create tasty dinners you can enjoy a few weeks or months down the road.

How about this Califlower Couscous.
http://food52.com/recipes/21165-spice-merchant-cauliflower-couscous
Serve with a tagine of eggplant, zuchini, mushrooms, onions...lemon rind and tomatos. Adding the cubed cooked lamb at the last moment to warm through.
Serve over the couscous. (And trust me...the cauliflower stuff is EXCELLENT--use the recipe posted or just the technique to make it your own).
Then add side dishes of Lavash bread, dips, herbs, and cucumber salads.

I was torn between a shepherds pie and lamb sandwich. But then I remembered a Moroccan dish and decided to fuss it with an Indian dish I knew, so I have some of my lamb in a sauce of Apple, onions, celery, carrot, thyme, cinnamon, clove, curry, garlic, curry paste, chopped tomatoes, chicken stock, and hot peppers. This will be serviced with rice.

The sandwiches sound delicious, I might be tempted to make a Shepherds Pie.

Slice thinly and make sandwiches with maybe some aioli, braised broccoli rabe, roasted red peppers.