Paint and build a front racked town bike

Stepping back a little bit, the aim here is to build a geared, flat barred run-around with a pizza rack and possibly even a wooden crate fixed on it.

I'd like something which I'm not precious about which can carry my bag or shopping without my having to take panniers. Also something which is a little bit more upright and leisurely pootling to work or the shops.

So, things that are certain:

• No drop bars (flat, riser and sweep back all to be evaluated)
  
• Pizza rack (will have to be QR/axle + brake mounted)
  
• Some gears
  
  • must be shifted at the bars, thumb or bar-end could be feasible depending on the bar choice
    
  • strongly prefer indexed
    
• Not an expensive build (e.g. I won't be buying a brand new 105 or above groupset for it!)
  
• Painted myself in a classic style, probably 70s british, head and seat-tube banding, and maybe a little extra flair if I can get decent results with more complex masks.
  
  

The main thing that is unclear still, and which I'd love suggestions for is the groupset.

Given the era and colours I'm going for with the paint, it should be silver. I have a few parts in the bits box which might be good, but nothing like a full group.

I've got a Shimano 600 crankset (the plain pantographed one, which I thing looks stunning in its simplicity)
I've got spare front+read Arabesque mechs, shifters and headset, but I don't think they'll suit the crankset and I'd like indexed gears at least. Were there ever 5 speed indexed shifters?
I've got some lovely svelte Mirage brakes, but they're single pivot, so not much stopping power for a loaded bike, and I don't want to do a Campy build, it just won't turn out cheap enough.

I've always though the DA-7400 series was stunning looking, plus it can be indexed :)

One potential plan is to get 7400 mech and match them with modern 8 speed Tourney / Claris / Sora thumb-shifters. Does anyone know whether the pitch or pull ratios have changed over the years. I've been reading, but I'm possibly more confused than when I started. I know the shifters will quite match the elegance of the rest of the bike(!), but I think I can live with it.

The other option in that vein is to get indexed bar end shifters, and some seriously swept back (to the point that the handles run almost parallel to the top tube) bars. But I'm concerned that the steering would be super twitchy when loaded at the front. How important to people find things like stem length and bar sweep with a loaded pizza rack?

I'll post some pics of the frame later. I'm trying hard to find some of it in the state I received it, but the ebay listing is dead cos it's too old and I can't find the ones I thought I took. There will also be the odyssey of the first attempt fork painting and its unfortunate end to come to get up to date on the project.

This is my first CP thread, hope I'm not making it too long already, but I wanted a record, and for anyone considering spray.biek to have a decent experience to refer to (which will come later...) because most of the ones I found online didn't go in to the kind of detail I was interested in.

If you've got this far, thanks for reading!