I am looking for seeds of:
Mandarinquat
Orangequat
Hong Kong cumquat or any other interesting cumquat hybrids. Do anyone grow these?

Mandarinquat and orangequat are quite often interchangeable often both are mandarin x nagami kumquat.

In the broadest sense the name covers everything from calamondin (sour mandarin x unknown kumquat) to Fortunella x obovata (putative hybrid) and nippon orangequat (unknown mandarin x nagami kumquat). I think F. x obovata is available in Australia but not sure about nippon orangequat.

May be able to do the Fortunella next year all fruit gone now, could be exchange for microcitrus seed.

Hong Kong Kumquat should be available in china town about chinese new year. It may be called golden bean kumquat or go under its cantonese name. If you are not going to buy plants yourself as calamondin is often used as a replacement.

I suppose the one I am after is Indio mandarinquat. It has a very distinct shape and colour.
I developed a particular interest in cumquats after rescuing a 30 year old calamondin from a garden that was going to be bulldozed by developers. It fruits almost all year and I make really nice marmalade with its fruit.
I since got few more varieties - Australian Sunrise lime, Myrtifolia cumquat (chinotto), Limequat (unknown to type) And nagami cumquat.
Would love to get other varieties like yuzuquat .

Indio mandarinquat.

Open pollenated seedlng from nagami kumquat originating in florida.

Ornamental but poor eating as very acid.