I usually don't see anything obvious on these things but here I do: Landscape.
There is a cluster of Landscape-related processes and one of these triggers
lshw. These processes account for a massive amount of CPU use. In my mind they're almost certainly making the difference between 60 seconds and 30, maybe even 20 seconds.
Assuming you have support from Canonical (Landscape being a Canonical Support feature), I'd have a really serious moan at them directly. If you don't need it, remove it and try again.
If you need it and you can't get Canonical to fix it, all I can really suggest is you suspend or hibernate instead of shutting down. Depending on your machine, suspend can actually be pretty alright. Our second-gen i3 laptop will last for about 4 hours on power but will sustain ~96 hours on suspend (usually enough to get to a power supply).
And all an SSD is going to do is speed up the disk stuff. If you look at the second graph, you can see the first third is the only part that's doing any disk throughput. I'm not saying they're not good - they're awesome - but they're not going to fix your problem.