almost certainly not, for the following reasons

1) Our whole 'thing' is providing broadband with masses of international bandwidth (we think 5-10 x more than other ISPs), amazing customer service....and absolutely nothing else.   That's why we don't do modems, anti-virus, email accounts, or IPTV services. We think most people who are our customers prefer to get their own, and in many cases can be found for free. We'd rather put our focus onto broadband and service, instead of being distracted by adding on bells and whistles. 

The only things we might consider offering on top of broadband + great service are things which you could not get except from your ISP (for example, a static IP)

2) there are loads of different unblocking services out there you can use - some of them are free - and we'd rather allow you the freedom to choose which one you want.  Personally I use unblock-us, but I'm considering switching to unotelly.  For a measly $5 or less per month, I don't see it as a big selling point.

3) Any service we offer, we want to provide great support for. We're pretty proud of the feedback from our customers - check our reviews on facebook. We don't want to wreck it by losing focus on the less important stuff

Now I don't want to bag slingshot here,  but their support for global mode seems to consist of "restart your modem, if that doesn't work, ask on geekzone"
https://www.slingshot.co.nz/global-mode/support-faq


compare that to the support you get with unblock-us.com , which consists of comprehensive device guides with setup videos, service listings, help articles, trouble ticketing systems.

http://support.unblock-us.com/
http://www.unblock-us.com/how-to-set-up/

unblock-us also support dozens of overseas services (Slingshot doesn't even list the services it supports, but it has stated 10, unblock-us has way more)

I just don't see the point in us trying to provide that sort of service, when there are vastly superior options out there that only cost a couple of bucks per month. (I believe you can get unotelly for about $3 per month) or are even free (like Hola)

For us to do it would take money and resource away from providing broadband and customer service - and that means either worse service, or higher prices for your broadband, and we don't want to do either of those things.

in any case, Bigpipe ($79) + Unblock-us ($5)  works out cheaper for you than slingshot's closest plan, naked unlimited, ($90) + Globalmode ($0) :D