Of course, there are some locos that will never be produced as kits or ready-to-run. Like the 1913 proposals for heavy freight locomotives for the L&YR and GCR, see below.
Thank you both. The lollipop sticks were the only way I could sensibly get the extra length I needed for the R-R, without compromising the strength of the chassis too much. Not done a drop test on it yet, and don't intend to do so.