The question was "where can I obatin the last cube made"

I am going to assume that last cube means "MAGIC POLYHEDRA", of
which there a three families: the cube with 3 axis of rotation, the
tetrhedron group with 4 axis of rotation, the dodecahedron group
with 5 axis of rotation.

The last original addition I have seen was a spherical SKEWB, april 1991.
Jean Claude Constantine (germany) is making shape/surface variants by
hand based on all three mecahanisms, eg, take a 3x3x3 and join together
(make in operable) one 2x2x2 corner - you can now change those pieces shape
anyway you want - by the way this type of restriction on the moves available
to solve the cube are very interesting. Also, in the spring of 1991
Christoph Bandelow has reintroduced the truncated octahedron and had the
Hong Kong factory complete from previously manufactured parts some 5x5x5's.

In my estimation there will NEVER be a last cube.

Solutions for all magic polyhedra, except the spherical skewb have been
published. First source is CFF ,cubism for fun newsletter of
dutch cubists club, some where also published in world game review.
Puzzles popular when ideal was in business where also covered by many
popular publications which are now hard to get. CFF has a library
and somebody has a bibliography of solution algorithms, including
Thistletwaites ??.

This is a general answer if there are specific questions please ask them!!

PS I sell much of this stuff and your US mail address will get you a listing
of what is available from me.

PPS I also collect this stuff and would like to trade and/or buy, any
quantity, ie, onesies to 100s. Not only puzzles but all things a
associated with the cube - books, patents, solutions, accessories,
promotional items, replacement stickers, what have you. a good overview
of this kind of stuff is in jerry slocum's book puzzles old and new.