In case you don't have that much to spend:
http://www.classictone.net/ - these guys have good iron, most likely best bang for buck. You can buy them from either one of their two distrubutors:
http://store.triodestore.com/ ,
http://shop.amppartsdirect.com/
Speakers are also VERY important.
And you should do some reading about carbon comp vs metal film resistors and what the benefits/shortcomings of each are.
http://www.aikenamps.com/ResistorNoise.htm
http://www.geofex.com/article_folders/carbon_comp/carboncomp.htm
If you want to get into the theory, here's some well written objective reading:
http://sound.westhost.com/articles.htm
This is also pretty good:
http://www.freewebs.com/valvewizard/
And this:
http://www.aikenamps.com/TechInfo_2.htm ;
http://www.aikenamps.com/TI_Aiken_Q&A.html
If you have some experience with PC drawing software (or want to get some), you could wait for all of your parts and then design a chassis based around them and on other popular designs/layouts and get it cut and bent at an engineering workshop for a reasonable price (a chassis would be one of the more expensive things to ship). You could also design your control panel labels and get them etched before you bend it up (much cheaper). I paid R400 for my most recent chassis, including material and etching of artwork/labels.
RS Components is great for things like switches, metal film/oxide resistors, electrolytics (really want to try the evox rifas on my next build). They also sell sockets and tubes, but I'd stay away from the tubes at least. The fact that you have to buy certain things in bulk (resistors mainly for your needs..) isn't too bad. Resistors are dirt cheap, and will comprise about R100-R150 in total, even in bulk. Nothing wrong with having some extras..
Some other nice suppliers of parts are:
https://www.smallbearelec.com/home.html
http://www.tubedepot.com/
http://www.turretboards.com/
http://mrvalve.wordpress.com/
I'd also suggest that its pointless to look overseas for something such as turretboard material; it can be a very basic insulated fiber board material and can be found very readily in SA without having to pay a premium. All you need then is some turrets (which you can get from RS) and a means to knock them in (anvil and stake):
http://www.turretboards.com/tut_building_turret_and_eyelet_boards.htm very easy to make your own.
http://www.maizey.co.za/engineering/engineering-sheet-rods-a-tubes/phenolics
Finally, if you're going to be building the amp yourself and if time permits I'd suggest to try and get as much out of the experience as you can. Do the reading, know your circuit and layout backwards and order all of your own parts; you don't need a kit. My experience is that you'll start replacing everything bit by bit if you get a kit.