Gigabit router/modem advice

Hi guys,

I'm just brainstorming at the moment, but I have a couple of questions. I'm a layman when it comes to networking, so don't be too harsh on me.

1) Not completely related, but why are there no internal or stand alone DSL modems in the consumer market?
2) Given that sourcing a Gigabit router with an internal modem is almost impossible to source is it a better solution to a) go for a cheap modem/router (Again, why no stand alone!) that just feeds through WAN (so not doing any routing) into an expensive gigabit router or b) get a good modem/router that routes into a gigabit switch?

What are the networking consequences? Am I being stupid? I would have loved to turn an old PC into a router/firewall with a switch combo, but it doesn't seem very worth it if there are no internal DSL modems.

TL;DR:
a) http://tplinksa.co.za/index.php?route=product/product&path=20&product_id=49 +
http://tplinksa.co.za/index.php?route=product/product&path=25&product_id=121

b) http://tplinksa.co.za/index.php?route=product/product&path=20&product_id=119 +
http://tplinksa.co.za/index.php?route=product/product&path=33&product_id=86

there's plenty of DSL stand alone modems

I have a tp-link 8817 and a Huawei (in a box as back up)

Ol' Mean Bastid said:

there's plenty of DSL stand alone modems

Click to expand...

There are? Because I can never find them.

Edit: And no, that one doesn't count. It can still route.

Garson007 said:

There are? Because I can never find them.

Edit: And no, that one doesn't count. It can still route.

Click to expand...

personally I wouldn't call one port a router, I've got mine setup purely as a modem, everything else is handled through my router

Ol' Mean Bastid said:

personally I wouldn't call one port a router, I've got mine setup purely as a modem, everything else is handled through my router

Click to expand...

I'm just being purposefully pedantic.

In any case, I still want to know if option A or B is better. I'm going to assume that the switch would slow down things, more than accessing the router directly.

Edit: Not to mention that if you take B and you run WiFi through the router, to connect to PCs - connected through the switch - with a wireless device, you'd be limited to a single 100mbit connection.