I also think the pre-season could be easily arranged to include a pre-season knock-out comp. Set down country towns for the games, then also set down venues where teams that are knocked out could play their second and, if they wanted, third trial. With the venues already in place, it would just mean that the teams would be decided upon by who lost in the first round - thus allowing sides to rest their top teams if they wanted, and not have to worry about quickly organising a second trial, if they were knocked out.
Some sides play three trials already, all play two, so at most this would be adding two extra matches to a sides pre-season, and if they are semis and finals of a knockout comp, with prizemoney for grabs, then surely the clubs wouldn't mind too much?