It would be great to be able to loan players to other guild members. In lieu of a youth academy, it would allow bench/reserve players to get more game time/experience. It would obviously need some form of checks/limitations to stop abuse, but I was thinking the following:

Players can only be loaned within a guild
Can be recalled at any time
Each player can only be loaned out once per season
All wages are payed by the loanee
No more than 3 loan players at any 1 time
No more than 5 loans per team per season

And how would you deal with player attributes ?

Agree with Taff. There's two problems regarding attributes, firstly you would only be able to loan to a player of the same level as you (or if you would like to make it complicated, a higher level) and secondly attribute assignment, who would be responsible for that? Your assignment according to stat and your guild partners assignment according to strat would probably be different.

Taff I'd quite happily loan some of your players and seeing as they are all 170 they'd just accrue training points for when they returned to you at the end of the season

A pint and two camels a day
Bonus pint for any tries scored

Camel cigars or actual camels? I may struggle with the shipping costs of the actual animals.

I'd block non-eligible players, and training wise I'd leave it up to the loanee - they are managing the player and its how it would work in real life. It's the penalty that you incur for loaning out a player for faster development

What about the camel ?

Get the camel a passport, costs incurred by the loaning team, then problem solved clearly

I just can't wait to watch a 170* player riding a camel and playing in championship level 1. What a great spectacle!