From the RPG.Net forums:

"I am the very model of a modern Trader's Seneschal.
I've information vegetable, animal, and mineral.
I know the price of produce and I quote the fights historical
From Cadia to Damocles in order categorical.

I am very well equated too with matters most heretical
I understand the Eldar both the Craftworld and piratical.
About the Inquisition I am teeming with a lot of news...
With many cheerful facts about their acolytes and retinues!

With many cheerful facts about their acolytes and retinues!
With many cheerful facts about their acolytes and retinues!
With many cheerful facts about their acolytes and reti-reti-nues!

I am very good at spotting fakes or any sign of treachery
My constant kind restraint conceals signs of my master’s lechery
In short in matters animal, vegetable or mineral.
I am the very model of a modern Trader's Seneschal!

In short in matters animal, vegetable or mineral.
He is the very model of a modern Trader's Seneschal!

I know Imperial histr’y from St. Drusus to Macharius
I unravel diplomacy on matters most precarious
I quote Sebastian Thor on the matters of divinity
And can recite all his sermons with unrivalled magnanimity

I can curse in seven languages with all manner of vulgarities
And steal from orphans and the poor and perishable charities.
At auction I can value what a man has never seen afore
And doing so sing praises of his holiness, Sir Malcador!

Then I can write a datascript in Necron circuit-cuneiform
And tell you every detail of my master’s finest uniform.
In short in matters animal, vegetable or mineral.
I am the very model of a modern Trader's Seneschal!

In fact, when I know what is meant by “Harridan” and “Hierophant”,
When I can tell at sight a Nurglish Death-Bloom from a potted plant,
When such affairs as surprises and sorties I’m more wary at,
When I return to speaking terms with all the Commissariat,
When I learn what progress has been lost in plasma gunnery
When I can do a week without accusal of a felony
In short, when I’ve a smattering of elemental strategy...
You’ll say a better Seneschal has never fought in zero-G!

You’ll say a better Seneschal has never fought in zero-G!
You’ll say a better Seneschal has never fought in zero-G!
You’ll say a better Seneschal has never fought in zero-ero-G!

For my military knowledge, though I’m dutifully and erudite
Is lacking both a tutor and any form of oversight.
But still in in matters animal, vegetable or mineral.
I am the very model of a modern Trader's Seneschal!

Again, this image was not originally purposed for the WH40k universe, but nevertheless offers a great insight into the portrayal of all those tech-priest characters.

Not 40K but still in our collective wheelhouse.

Ah, Gav - I see you too have been reading Into the Maw: Or how I became Incredibly Wealthy. I've always liked Cornelius Crime's Autostabilised Hat. I heartily recommend it for all rogue traders (although I think he did work out that he'd written near a novel's worth, so it could take you a while).