The plans will be put to the SPFL and Scottish FA before clubs are asked to vote on them, report the BBC.
The proposals would see Celtic and Rangers enter reserve sides in a 16-team fourth tier with two sides from both the Lowland and Highland League also joining.
The 20 clubs in Leagues One and Two will be granted £100,000 over five years, while the current movement between the SPFL and the winners of the Lowland League and Highland League play-off will remain.
The colts teams will have an age limit of 21 and won’t be able to win promotion from the third tier.
In addition, strategic partnerships have also been discussed with loans of under-21 players between clubs increasing from two to five.
The working group have presented their proposal to the Professional Game Board within the Scottish FA.
Meanwhile, at time of going to press it remained uncertain as to if and when there would be any resumption of the 2020-21 Highland League campaign.
It is abundantly clear that, as long as Covid testing remains mandatory, the huge costs involved in regular PCR testing for all players and management teams within the Highland League would be unaffordable for sides at that level.
However, if the rate of coronavirus continues to drop across Scotland amid a strong vaccine rollout, there could be a scenario whereby restrictions ease enough to allow the Highland League to resume.
The whole country received a welcome boost on Tuesday when First Minister Nicola Sturgeon announced the long awaited route map out of lockdown.
A series of steps over the next three months will see reopening of the economy – including pubs and restaurants – and the return of socialising with friends and relatives.
Although Sturgeon did not give an exact date for the return of sporting events, gigs and nightclubs, she said: “I am optimistic that this date will be over the summer.
"I know I will not be the only one looking forward, with a real sense of hope, to hugging my family this summer.”