Interesting yes, not so practical. Oz did have a heap of these from the Navy, they sat for years corroding away until they were finally sold for scrap. Just to convert to turbine power 3 million plus, another million to install a 4000 litre hopper and for the CASA paperwork. The delay in CASA processing add another million and 5 years.
When they become operational they cost 3 times what an 802 cost to operate and deliver only 500 to a thousand litres more than an 802. You have spent maybe 5 million per aircraft compared to the cost of an 802 at 2 million. Top that off with nobody being prepared to cover the cost of any of this the government would have to pay bringing into play another level of bureaucracy and delay. Todays fleet of 802's are all privately owned and available at no cost to the tax payer, only call when needed or on contract standby cost.
I am no fan of large air tankers, I am a big fan of very large air tankers. The current fleet of lat's in Oz from Herc's to 737's usually only drop up to 11,000 litres. They say they drop 15,000, they don't. 11,000 is still a good load when used rightly. Personal experience is few LATs drops are effective, too light, too high.