Base units are normally 600mm deep not 450mm so that could be the reason you can’t fine one. Is that what you mean?

Alternatively do you mean a 450mm door on a 900 straight corner base? If so Hafele offer this:

The Hafele website got hacked just over a week ago and they are in the process of rebuilding it so no prices are available for trade customers but we can now see what they sell. Vauth Sagel is not cheap but the quality is excellent.

The unit is 900mm wide x 450mm deep and standard height

If you saw the design, you would realise why but I don’t want to post it because it is technically the designers and I don’t want to upset anyone !!

Why have you got 450mm deep base units and not the standard 600mm deep? If such base pull outs are designed for a standard 600 then unfortunately l doubt you will find one to suit.

Kidney shaped ones in my opinion are a waste of storage space.

As @Daisy England has indicated, you will struggle to find a suitable wireworks, as almost all are sized for full depth units of minimally 560 (less the void).

While I acknowledge Daisy's concern re use of space of the kidney style wireworks, my experience is they are4 by far the most robust mechanisms. If you opt for one of the rectangular "track" style ones like that shown, stick to a quality brand like Vauth Sagel or Kessebohmer, as many of the others are far too easily damaged by overloading or "leaning" on them.

Dut I still think you're going to struggle. I did find one designed for a 400w door once, which might work but unfortunately can't remember the brand (it wasn't one of our usual ones).

I wish you luck in your search though would say you may not be successful, sadly.