BunnyMade

http://parts.singerco.com/IPpartCharts/ <- For part numbers/images and they sometimes have good exploded views of machines. http://parts.singerco.com/IPinstManuals/ <- For the "User Manuals" (sometimes I've found the service manuals here too). http://parts.singerco.com/IPsvcManuals/ <- For the "Service Manuals" (found that these are much fewer, and some are user manuals). I always keep a little bucket of scraps near my 29k to keep testing tension until I'm happy with the results. A picture might help, I guess?

From my brief perusal of the manuals, it appears that they're both light to medium weight machines, if you were handy enough could make something aftermarket to exploit Singer's propensity to have all the holes drilled in the body regardless of model variant - they both could come with edge trimmers and guides. The 153 says it'll do 2900 spm, vs 2500 spm.. Having not owned one myself, I can agree that they shouldn't cost you nearly as much as the snazzy machines that do everything but walk your dog. What's your opinion of "heavy" material, is what it really comes down to. http://parts.singerco.com/IPinstManuals/153K101_K102_K103_154K101.pdf and http://parts.singerco.com/IPinstManuals/46W61_W62_%2047W61_W67.pdf should help a little bit more, hopefully.

The leather buttons that toolingaround pointed you to can work for most of what you initially indicated you're looking to accomplish. Since you mentioned straps in the last post, I'm assuming you mean shoulder straps for wearing? If so, even without hardware it still can be accomplished; adjustability will take longer, though. http://www.trackofthewolf.com/Categories/PartDetail.aspx/423/3/BAG-TAIL is a good example of what I mean.

Check Craigslist in your area, I seem to run across REAL industrial machines every once in a while for cheap (for instance, there's a machine worth checking out in Grangerland (Houston CL) for $400). DON'T fall for the so-called industrials with 1/2" leather - if they don't have to be placed in a table with a heavy duty motor mounted underneath, it's NOT going to do what you need. Inquire at an upholstery shop where they get their machines serviced; industrial machine servicers usually have some used machines that you could get on the cheap. You're in Texas, so I'm pretty sure you've got saddle and boot makers a-plenty. They're also a good resource for used machines and information in general.

2$ for a spike and I gotta bend it myself? Feh. My clumsy self would mar the finish every time. Some constructive thoughts on your photo: put your item on a neutral background. If you have problems with the chrome being too shiny, stuff it in the freezer for a few moments. The reason I say this is because I'm having a hard time focusing on the work and not the mar... OOH SHINY!

Those rolled edges on the posture collars look more like piping with some sort of padding, but I could be wrong. Check out upholstery stores, they make something called "mopcord" or welting cord in different thickness and spongy-ness. As far as appropriate goes for fetish gear, I think it's better to be sure that the wearer isn't injured by accident or from poor workmanship. However, keep in mind: the more simple you make your items (grooving/bevel/etc), the more likely they are to last. Stitching does come loose, and I find that my clients get very attached to gear - especially when it's made custom order. I've had more than a few folks come to me with other peoples items and beg me to fix mistakes, filling my ears with complaints of the salient details of how it failed. Also, if you find the maker of those spikes in pic 3.. mommy want. :D