Here is one I took today, Love the colours at the Royal Exchange.

That is a strange one, as in the past there was no issue. Maybe it is Ricoh playing hardball, maybe Tamron see the share that Pentax have is very small, maybe it the the Sony influence. Possibly all of them?
Mind you the 18-270 is a Tamron in all but name, so in effect there is no real animosity between them

Who knows we may even see this lens badged as a Pentax with Pentax coatings and add 1/3 to the price.

Oh if only we could have the delightful Tamron 60mm F2 macro on Pentax mount. But I just keep saying that.....

There seems to be a plethora of options for your needs. Depending on the focal ranges that you need.

Option 1
The Q system as already mentioned. Small, light, cute and flexible. But due to small sensor the "creative" shallow DOF looks won't be there. Is that important or not?

Option 2.
18-135 (if you need Weather sealing) 18-270 if you don't, and include a 50mm F1.4 or F1.8 for Shallow DOF shots

Option 3
Keep the 50-135 or 60-250 and add some primes like 15, 21, 35 and a fast 50.

Option 4
Stick to primes. 15mm, 21mm, 35 F2.4, 50mm, 70mm and 100mm Macro. This will reduce the weight a lot but you will have to keep changing lenses. You could drop the 21 and 35 and replace with the 20-40 limited.

Option 5
16-50 and the HD55-300, and add a fast fifty. Again nice and light with a great focal range.

The choice is yours.

Well, in the end, I went for the 10-17mm. And Guess what, picked it up at lunch and walked around Manchester. I LOVE it......

It's for a mirrorless. Ricoh GR "35mm" perhaps?

Quite often at lunchtime in Manchester. I am slowly building up my confidence in this regard.

Mind you with that recent new item about Hungary, don't bother trying it in Budapest. (shame really as it is a great place to do it)

I think he may be confused. 200ISO was the native ISO for CCD sensors, still is really. I am sure that the native ISO for CMOS is 100ISO.

Mind you in reality, it all depends on the make and model of the camera.
For instance the Native ISO for Canon is 100ISO, Nikon around 160ISO. Leica Monochrom, 320ISO
My K20D has a native ISO of 200, yet my K-5 is 100.

So, if you have been shooting your K30 it 100ISO, you won't have a problem.

Some options for you.

1. DA35 F2.4 - Yes I know it is longer than your focal range requirements, but boy it is good.
2. Find an F28mm F2.8, super sharp and around the £180 mark to get one
3. Tamron 17-50mm F2.8 - Very good alternative to the DA*16-50
4. DA* 16-50 - Matches the DA*50-135 and weather sealed....

I downloaded it last month. Looks great but it is so resource hungry. So as a result I am doubling my RAM on the laptop.....

Peter is right, Photoshop is very resource hungry, even older versions. 512MB RAM will struggle a lot.
Have you thought about replacing your computer with something more modern? I know it is a cost that you may or may not have, but then again, having a new computer or laptop, and having a more recent version of Photoshop will provide you a lot better performance, and usability. Plus having a more recent operating system you will have the peace of mind that the security will be bang up to date when you are on the internet.
I think that having a Gateway computer with only 512mb RAM that you are running something older than Windows XP (itself no longer being supported by Microsoft after April). You may find that having a new laptop with say Windows 7 will be many times cheaper than what you paid for the computer you currently have.
And don't forget, Adobe do provide the option to download a copy a Photoshop CS2 for personal use only for free.

As for RAW files with the K10D, people have already answered that question, but I have found, that newer bodies like the K-5 are much more pliable when it comes to highlights and shadows than the K10D. But Worry not, the RAW out of the K10D are far better than the files out of the K20D, as I have found.

Hope this helps, but I know the savings will take a battering.