Special Request Line 9

Nerd goes back in time to change a jock that bullied him into a nerd girl, but causes a ripple that turns the nerd into a girl as well and they end up as lesbian girlfriends.

Sara Smith

How about a classic Star Trek transponder malfunction? A Starfleet team beams down for a mission, but reappears as female versions of themselves. Doesn't have to be specific characters, random people in Starfleet uniforms is fine. They attempt to turn themselves back by using the transponder again, but it turns them into bimbos instead. Que the commander grumbling how "Kirk never had to put up with this shit."

Man creates mind control helmet and uses it to control the body and movements of a young woman. However, as he uses it to control her, it creates a feedback loop he doesn't notice that changes his body into hers.

fishalee

Buff space ranger turns into a retro pinup space girl in distress.

Alpha 01

Any particular heroines?

Zac Crockett

I think that Space Jam alien transformation would fit your style quite well. Just be sure to have them accidently steal the talent from a bunch of cheerleaders instead. ;)

Joel

Marty Mcflays time travel Deloreon malufunctions and he gets absorbed into the 50s by getting transformed into a typical 50s girl.

Semmel

After being hit by a mysterious gas from a Xenomorph Egg, Ripley from the Alien Films (specifically Aliens) slowly shrinks, dropping her increasingly heavy gear and clothes before being chased by a now equal sized face hugger

Elliott Waring

A scientist uses a reality-warping device to jump Quantum Leap-style (but with morphing!) into the bodies and movie/TV plotlines of some well-known SF heroines. ( No wallflowers! Thinking maybe Ripley, River Tam, Leeloo and Barbarella?) Danger and/or sexy hijinks ensue.

Dave Chin

A hacker dives into a futuristic fantasy VR game, then hacks it somehow to change themselves into a catgirl. In the real world, they've become a cyberpunk catgirl (maybe a side-by-side sequence where they're shown changing in the virtual and real world simultaneously).

Erin Brioche

It's a little tried but true, but Star Trek: The Next Generation characters (Picard, Riker, Worf, Geordi, Data) beaming off the Enterprise and onto a planet with strange, highly feminine iconography that interferes with the beam-in process. They re-materialize as incredibly attractive women in their Spandex uniforms...Which they then discard as they're captured by some alien slavers (Cardassian, maybe?) and become 'comfort women'.

Mr. Domino

Hm, Matrix agents overwriting opposite-gender civilians (or hacking into some of the heroes?)

Carolaran

Prequel Obi Wan hides out from sith by changing looks, but it takes a feminine twist.

Skippy Hugo

A handsome Asian scientist injects himself with a serum, turning him into an equally attractive, big breasted white female scientist with blonde hair

x_cexoztykl

From to love ru. Rito clumsiness accidentally drops lala's transformation gun and shapeshifts into various female characters in the series.

THATS A TOILET

a woman is abducted by two aliens but she uses their technology to turn them into an asari from mass effect and a female twi'lek from star wars. then they become sexy lesbian space pirates

Pascal

I would say either A new type of facehugger shows up - not as lethal, but may cause significant swelling. or A little mixup using the transporter pods (a la "the fly")

thrandrall

Okay this is a weird one but here it goes. A group of teens girls who merg together to form the ultimate woman? Have each one be of a different race/ethnic background bur have their combined qualities merge to form the ultimate woman form. I understand it is a loaded concept but it kinda has a message behind it.

Ghost909

Marvel: Skrull agent testing his shapeshifting power by transforming into marvel superheroines

birds45

An astronaut crashlands onto an alien world and begins to morph to match the local inhabitants. Too bad for her, said inhabitants carry a rather feminine charm.

Alex James

Warhammer 40k: An Ork and an Imperial Commissar are fighting in the middle of a war zone (that just so happens to be an Eldar Maiden world) when suddenly, they and anyone on the battlefield are transformed into Eldar women.

Mas alan

A man gets injected with nanites that turns him into an Amazonian woman.

Somaria

Astronaut/cosmonaut TF-TGed into Retro Sci-Fi Pinup girl

Dudeface1941

Dr Jekyll and Miss Hyde tg sequence remake would be nice since the original movie didn’t give enough onscreen full body transformation

Arxynos