I found something you may like

Much simpler solution: get the Chatsford mug infuser, which fits inside most mugs and lifts out, so you don't wind up steeping your tea for half an hour.

dmh

For what it's worth, Chinese green teas don't seem to care much about being steeped a long time, but Japanese green teas can get very displeased about being oversteeped. There are exceptions of course, EG I have a Chinese sencha (strange, yes) which would be harsh if I steeped it for more than a couple of minutes, but it seems quite plausible that this is because it's a Chinese tea produced in a Japanese style.

Argh...Not an another gimmick!

As if a real teapot isn't going to the job.