Upgrading Bicycle Gearing I have a Raliegh falcon touring frame, which I've been upgrading gradually as it's in good nick, putting modern componants on it.  

I've got to the point where the next thing I need to do is upgrade from down tube shifters, ideally to combined brake/shifters.  I've got a triple chainring on the front (sora) and 6 speed on the back, with 27 x 1 1/4inch wheels. The rear shifter is indexed, whilst the front is not.  I'm aware I'll probably have to install a new rear derallier at the least.  

So I have two questions.  Can I get any more gears on the back?  Do they make 7speed rear cassettes for older bikes?  

And secondly, looking at sheldon browns website, the Campagnolo "Ergo" set would let me keep the front unindexed -am I correct?  And is the rear shifter modfiable to a 6speed, if I can't upgrade the rear cassette?

Thanks
Not brifters, but you can take your downtube shifters and use retroshift levers to get combined brake and and shifting. Essentially, they bolt a downtube shifter onto the hoods. Pretty cheap and reviews are generally positive. 

As for fitting more gears, you may be able to get a 7 speed freewheel, but you may better off taking your 6 speed freewheel to the LBS and swapping it one with better spacing between the cogs. 

Tires in 27" aren't too limited (Conti makes gatorskins in 27 inch, panaracer has some, etc.). But if you need to move to 700C, you need to make sure you can move your brakes down by 4 ish due to the 700c diameter change. The selection of new 27" wheels is more limited though (Sun CR-18, etc.), though can be found.