I've been writing a lot of Steampunk-related stuff this month recently to tie in with the release of Cogs In Time 3, a Steampunk anthology which I'm part of (and which you can now buy in physical book format!). As a result I've been doing a fair amount of research into Steampunk things, and I've come across a lot of conversion work. I wanted to showcase some of the better stuff I've seen.
I absolutely have to start with this steampunk Nerf gun by Dr Kayleigh Wardell mainly because, unlike all the others, I've actually seen this one in the flesh. It's a pretty awesome piece of work, because it's still a functional Nerf gun while keeping that steampunk aesthetic. If you're at all interested in how to make Steampunk-esque things, there are plenty of guides out there on the internet. But a good place to start is these process photos that Kayleigh took while she was making it.
There's a goodly selection over at Steampunker.de, including a few things that 'cross the streams' of cult entertainment, like the Borg headpiece and the Optimus Prime head. A lot of the conversions keep the 'practical' elements intact, such as the memory stick above, or any of the several clocks on display there.
There's even a design agency for this sort of thing, ModVic; they have some awesome stuff there, like a steampunk wheelchair, and an entire house conversion. Go check out their site, it's pretty immense.
I think, as a style, it would be quite impractical to try and live a 'Steampunk life' in this day and age. There's a reason that steam engines have been outmoded as a power source on a personal level. But I can't get around how cool some things look when they're modified to be 'steampunk-esque'.