Well I have been waiting a day for someone to drop this line and no one has. So I will.
You know an Internet forum thread has reached classic form when we get our "knickers in a knot."
Ishna ji is asking some practical questions, and I wish I knew the answer. Who wants his/her kechera all bunched up? The distraction of it seems to defeat the purpose of kechera from the beginning. Here are some things from the thread so far that puzzle me, and I hope Ishna gets answers to the questions she asked.
1. Going commando does not match well with the vows taken at amrit sanchar.
2. Who knows what women wore under their outer wear in the Gurus' times, just by looking at photographs?
3. The only Sikhs that I know of who do not wear kechera under other pants/trousers/salwar are Nihangs. For all others, kechera are underwear. But then I don't know it all.
4. First written mention of kechera was probably in Bhai Nand Lal's rehit, and most likely mentioned in other sources, which I cannot cite off the top of my head.
5. Today, the Sikh Rehat Maryada requires kechera of both men and women. So these are part of the 5 kakkars, though I would avoid the term "uniform." The kakkars are articles of faith. "Uniform" does seem to stress a "look" rather than a state of heart and soul.
6. All Ishna wants to know is how to make/construct kechera that are compatible with modern dress. She is not conflicted about whether a Khalsa wears them, or does not.
Tradition tells us that the kechera were designed as an improvement over dhoti by Guru Gobind Singh, and were worn by his fighting force before the first Baisakhi. Why would a Sikh warrior want to be caught with his dhoti down? This again cannot be proved, but the common sense of it persuades me.