The original "price limit" which has been loosely observed, was $1750 to build in 2001 dollars.
So approx $3200 today or £2370.
You have some leeway yet 

JimR

I am experimenting with a (mainly) no weld aluminium chassis. Be aware that it is an experiment but here is my process so far.
The chassis long members are a heavy duty ladder with D section stiles. The cross members are 40x40 mm aluminium box and held in place by 40 x 40 x 6mm. aluminium angle. The main joints are then fish plated. All the joints are first well prepared with the oxidation removed and glued with MMA structural adhesive on all parts then riveted. Properly applied in good conditions MMA will have the shear strength of 2 number 8.8 grade M8 bolts on a 80mm x 40mm surface area (my typical area of each joint). It is more resistant to shock than most commonly available epoxy resins.
From the construction I have completed so far this seems to providing strong joints. Time will tell.
This fellow has a video of bonding aluminium with various adhesives, although his pronunciation of Methyl MethAcrylate might be a bit suspect... https://youtu.be/4dgZ-vcc0hQ?si=hHIpTz3gp1CfI3pr

As I mentioned at the start, experimental!

JimR

Great to see a new build journal Matt, looks like a very positive start. 
JimR

Moving the rack forward or rearward of a straight line on plan wheels straight ahead, take off point to rack to take off point alters Ackerman positively or negatively - see drawing below. So you have a little to play with if you want to get it bob on. I doubt it will amount to much difference in feel but if you are a purist, this avenue is open to you.
JimR

I pretty much did the same as Granville, no issues to date
JimR

Good question Stefan, I forgot to mention what I was talking to Steve about in the post.
The jackshaft from Gemini that replaces the TAV2 one but with an extended inner is pictured below. It takes the standard TAV2 sprockets and was the one I was talking to Steve about, From memory, I was talking to Pred about a similar set up for his Rat by using the shaft as a jack shaft. It is fat in the middle to suit the TAV2 bearings and keywayed both ends for the sprockets with a thread both ends for the nuts. It is about 250mm long. The closest you could mount the sprockets to each other woud be about 90mm centre to centre.
JimR

No reason why not, other than you could use the ratio to make the final drive more compact.
JimR

Provided you can support the shaft with a bearing and the drive is the right way, no worries, I played with the Tav in different positions but drawing the bearing support was a bit iffy, you could copy the drawing and mess with it
JimR