I didn't post this earlier because I was worried that it was just a fluke, but it seems Transdesign are shipping internationally again... Well at least to Australia anyway!
I placed two orders with them last week for 9 bottles each order and was only charged 18USD shipping for the flat box, which is the same as what it used to be. The orders haven't arrived as yet, but it is saying that they have shipped and I was provided a tracking number, so that's a positive sign!
I also noticed that the "OPI Liquidation" banner has been taken down and there is no indication that they will not be stocking OPI in the future. This is GREAT NEWS!
Admittedly, their prices have gone up quite a bit in the past couple of months - OPI is now $5.24USD per bottle and Essie are now $8USD per bottle, but the prices of the other brands seems to be the same, so I'm still happy! :D
I hope that things have returned to normal for good! :D