Have you tried the Petite section at Topshop? They do a good range of trousers for shorter women, and none of them would have a high waist I wouldn't imagine- Topshop are far too cool for that! I do know that they do a massive range of black work/evening trousers.
I have the opposite problem, being nearly 6ft tall, but the Topshop Tall range works for me, so maybe the Petite range will work for you! Actually, I have just had a look on the website, www.topshop.co.uk, and they have some nice herringbone and tweed trousers too which would do for work.