There was a T/A I used in the late 80's early 90's that did a Keema Royale which was a sort of Keema/Bhuna/Dopiaza with minced meat, peppers, onions, peas and was garnished with a quartered boiled egg, very nice it was too. Just try a sliced boiled egg as a garnish for a biriani or any curry for that matter, absolutely delicious. Hope this helps.
CoR

OK. Did a simple lamb madras last night, usual way only substituted my base with the stuff from the jar diluted 50/50 with water and upped the spice mix (BE) to compensate for the absence of spices in the base, the results were actually quite good.
That's not to say we can all just call it a day coz I don't think it is better than a "proper" base but it's quite an acceptable stand by to have handy and miles better than any of the curry pastes, especially the Patak ones which I find particularly nasty.
Thing is though for the ?1.30 it cost I could have made 3 litres of base, I'll be lucky to get two decent portions out of this, oh well that's the price of being a lazy bugger I suppose.
CoR

...I have never (yet) seen one for just the plain curry base though. 

Hi CA

What about this stuff http://www.eastendfoods.co.uk/nishaan.htm it's in most supermarkets but I can't comment on wether it's any good or not never having tried it, has anyone on here?

you could use a (tiny) pinch of red food colour if you want...

CoR

I also think it could be really versatile by using different spices blends.       

Versatile indeed, try it with Stilton cheese on crackers, very nice! It's also worth blitzing a little Greek yogurt (5 parts banjara/1 part yogurt) with it, seems to add an extra dimension to the final dish.
CoR