I have found on-line retailers selling the TRF-5300/5310/5320. They are twin-tuner quad-recording PVRs with IceTV Interactive support. The only difference in the three models is the size on the internal HDD (500gig/1TB/2TB).
They appear to be replacements for the TRF-2400/2460. The specifications indicate that they run the same generation firmware as the 2400/2460. The main hardware difference is the absence of component output and analogue input.
It is not clear for the specifications if the support TAPs. Topfield Technical support advise that they do NOT support TAPs.I have attached the TRF-5320 information brochure.
There is no mention of the new model on either the Topfield Australia or Topfield Korea www sites (strangely this is not unusual conduct by Topfield).
Update 27-09-15: According to the Topfield Australia WWW site the TRF-5300 HD supports TAPs (see http://www.topfield.com.au/products/new-product/trf-5300-hd/); I cannot vouch for the accuracy of this statement.
I tested the 5300 about a month ago to ensure that IceTV was working correctly on it. I didn't try to load any TAPs, but firmware wise it seemed identical to the 2400/2460 PVRs.
The only noticeable differences are the new style remote control (which recent 2400s also come with) and no component output and no analogue input.